When I started this blog, I would sometimes write posts where I’d ponder some scientific issue, mainly illustrate my own ignorance, and benefit from those who are more informed than me telling me where I was going wrong (which is different to those less informed than me telling me I’m wrong 🙂 ) . I thought I might resurrect that by writing a post about something I was considering with respect to the greenhouse effect.

A somewhat contentious issues in climate change is the role of feedbacks. A basic way to think of this is that there is some external change (Sun, volcanoes, us) that, by itself, would produce a certain amount of warming or cooling. This warming, or cooling, then produces other changes (feedbacks) that produce more warming or cooling. The final state is then set by the combination of the forcings plus feedbacks. Kate Marvel has a very amusing, and very good, blog post that explains the basics of feedbacks.

The greenhouse effect refers to the fact that our surface temperature is 33 degrees higher than it would be if our atmosphere was completely transparent to our emitted radiation (assuming a fixed albedo). A 33 degree increase in surface temperature is associated with a 155 Wm-2 increase in surface flux, or a 122 Wm-2 change in radiative forcing (33 x 3.7Wm-2). The actual number isn’t that important for this discussion, though.

Prior to the increase in anthropogenic CO2, the atmospheric CO2 concentration was about 280ppm. This would contribute a radiative forcing of about 30Wm-2, so about 20% of the the overall greenhouse effect. Other factors (water vapour, lapse rate, clouds) have to then provide about another 100Wm-2. Therefore one could argue that the feedback response is about 3Wm-2K-1 (100Wm-2 / 33 degrees), or that feedbacks amplify the warming by about a factor of 5. Given that a doubling of CO2 alone would produce a warming of about 1 degree, this would imply an ECS of around 5 degrees (and since the albedo is fixed, I think this would be an ECS and not and ESS). For comparison, an ECS of 1.65 degrees (as suggested by Lewis & Curry 2014) would require a feedback response of around 1Wm-2K-1. Most climate models suggest a feedback response of close to 2Wm-2K-1, giving an ECS of 2.5 and 3 degrees, which is also consistent with many paleo estimates.

So, does the greenhouse effect allow us to constrain the feedback response in any way? It seems clear that it illustrates that feedbacks have to be positive, but apart from that I’m not sure that there’s much more that can be said. Some issues I can think of are :

we don’t expect feedbacks to be linear and maybe the change in climate state is simply too great compared to what we’re undergoing today.

maybe it’s not really a situation where we can break it down into a forcing plus a feedback. However, given that the CO2 is primarily (I think) from volcanic outgassing, it seems reasonable to regard it as an external forcing and the rest as feedbacks.

you actually need to know what the water vapour, lapse rate, and cloud conditions would be prior to any warming, as these could provide an initial forcing that I’m including as a feedback, reducing the feedback response.

Anyway, I’m not sure this post makes much sense (in fact, it’s sufficiently muddled, that I considered trashing it, but maybe someone can make some sense of this). Even if the average feedback response that contributes to the greenhouse effect is about 3Wm-2K-1, I’m not sure that this is really an argument against the low feedback response suggested by Lewis & Curry (2014). On the other hand, both the greenhouse effect, Lewis & Curry (2014), and virtually any other sensible study, suggests that feedbacks have to be positive, so maybe that’s something.

I definitely fall into the category of someone who’s less informed than you, so I’m not going to say you’re wrong 🙂 , but…

Isn’t there a hysteresis effect here? If at an earlier time the atmospheric concentration of CO2 was much greater than 280ppm – enough to warm the planet and increase the atmospheric concentration of water vapour, etc. to get a >33 degree increase in temperature – then when the CO2 level dropped back to 280ppm, the water vapour would still be at a high concentration, maintaining much of the temperature increase. In other words, what I’m trying to ask is – is it correct to consider all the 100W/m2 as a feedback to the 280ppm concentration of CO2?

is it correct to consider all the 100W/m2 as a feedback to the 280ppm concentration of CO2?

Quite possibly not, and is one of the things I was wondering. I think, though, the issue is what would the radiative influence of the other factors be if we were 33 degrees cooler (i.e., do they provide some initial radiative influence that I’ve included as a feedback, but that isn’t).

However, if this were the case,

If at an earlier time the atmospheric concentration of CO2 was much greater than 280ppm – enough to warm the planet and increase the atmospheric concentration of water vapour, etc. to get a >33 degree increase in temperature

then I think it would be the case that treating it as a feedback would be correct, given that it is still the CO2 that is fixing the initial temperature rise and the other factors are responding to the temperature changes (i.e., they’re feedbacks).

For a 1.1K increase in temps from doubled CO2 (and other GHGs) or about 4.2 W/m2 of forcing:

–> the feedbacks then kick-in from the initial +1.1K temperature increase which produced a second round of temperature increase which then provides for another round of feedbacks on that temperature increase, leading to another round of feedbacks etc. etc. … after about 11 total rounds of feedbacks on feedbacks, the temperature changes dampen down to near zero and we have reached equilibrium …

—> so, the initial doubled CO2 forcing is +4.2 W/m2 and the feedback forcing at the troposphere becomes +7.5 W/m2 and the total forcing is +11.7 W/m2 which provides for …

—> 3.0C of increased temperature in the troposphere and at the surface according to the Stephan-Boltzmann equation.

It is almost never explained this way but that is how the math works.

Now change any of those feedback parametres above and you get a different result. Build a calculation model using the Stephan-Boltzmann equation to check it out .

Bill,
Yes, your explanation is certainly correct, but where does your 4.2 Wm-2 come from? Normally the forcing due to a doubling of CO2 is 3.7Wm-2 and produces about 1.1 degree of warming by itself. Your feedback numbers give 2.45Wm-2K-1, or 2.7Wm-2 per 1.1 degree. This is 0.72 of the forcing due to a doubling of CO2. You can write the resulting warming as

where . This gives an amplification of 3.7, or an ECS of about 4 degrees. Of course, there are all sorts of uncertainties and things, but that’s about the kind of numbers I’ve seen (maybe a little higher, but no need to quibble over a few tenths of a Wm-2).

” Formally, the Climate Feedback Parameter (α units: W m–2 °C–1) is defined as: α = (ΔQ – ΔF)/ΔT, where Q is the global mean radiative forcing, T is the global mean air surface temperature, F is the heat flux into the ocean and Δ represents a change with respect to an
unperturbed climate.

As we are comparing (purportedly) equilibrium conditions, ΔF = 0, and therefore we should be calculating α as change in forcing/ change in temperature. That is, on the assumption that the water vapour and clouds only exist in the atmosphere due the the presence of greenhouse gases, α = 32 W/m^2/ 33 K, or approximately 1. That corresponds to an ECS for a doubling of CO2 of 3.44 for effective radiative forcing. (The 32 W/m^2 is the single factor addition for all WMGHG from Schmidt et al (2010) below.)

2) The estimate of CO2 contributing 20% of a total 150 W/m^2 total greenhouse effect comes from Schmidt et al (2010), and is a model based estimate using “c 1980 conditions” of 339 ppmv.
3) That paper has a sister paper, Lacis et al 2010 which shows the consequences of complete removal of the Earth’s CO2, keeping land ice fixed. It shows a drop in GMST of 34.8 C, an increase in planetary albedo from 29 to 41.8%, and water vapour to drop to about 10% of current values. Only 10% because there exists a band in the tropics with annual average surface temperatures above 0 C. One difference between the two sets of experiments is that Lacis et al shows a change from pre-industrial conditions, and shows an initial drop of 32.5 W/m^2 for the initial removal of all CO2. That compares to a “single factor removal” effect of 21 W/m^2 (14%) for the slightly higher c1980 CO2 concentration calculated by Schmidt et al. (Another key difference may be the use of a Q-flux version of Giss Model E to allow approach to equilibrium in a short time).

From this I do not think we can conclude that removal of all CO2 will remove all of the WV from the atmosphere, nor is the 33 C drop in temperature set in stone. Consequently you are not entitled to assume either a drop of 100 W/m^2 in feedbacks, nor the 33 C response. Using the Lacis et al figures, you have a 35 C response to a 32.5 W/m^2 initial forcing, or α = 0.93 W/m^2 / K. Based on Schmidt et al, and assuming the same temperature response, however, α would be 22/35 = 0.63 W/m^2/ K (single factor removal).

The key point here is that even using essentially the same model, there can be significant divergences in the value of α calculated by different approaches. The divergence will be still larger using different models (and of course, we can only flesh out intuitions on these points using models). Therefore such estimates are at best sanity checks. Given the range of conditions across which the model must work to do the calculation, as a ball park figure I would suggest that if our estimates differ from such estimates of α by more than a factor of 10, we really need to revise our estimates. That is, if our estimates of ECS are below approx 0.37 or above 37 we need to think again, but we already knew that 😉

It is probable that these calculations can be a more restrictive sanity check, but short of a series of model experiments for little gain, I do not know how we would constrain the range. My feeling is the sanity check values are within a factor or 3 or the genuine value, but I certainly don’t know how I would demonstrate that to somebody with different intuitions.

Tom,
Yes, you make some very good points (I wrote this partly with you in mind). Your point that is well made and I should have noticed that. So, it does seem as though there are plausible arguments as to even the greenhouse effect given and ECS around 3 degrees.

With a straightforward scheme for allocating overlaps, we findthat water vapour is the dominant contributor (50% of the effect), followed by clouds (25%) and then CO2 with 20%. All other absorbers play only minor roles. In a doubled CO2 scenario, this allocation is essentially unchanged, even though the magnitude of the total greenhouse effect is significantly larger than the initial radiative forcing, underscoring the importance of feedbacks from water vapour and clouds to climate sensitivity.

So, it seems that ignoring slow feedbacks means that the actual climate state is not that important.

By my calculation, the total greenhouse effect with doubled CO2 and a climate sensitivity of 3 is 168 W/m^2, so an increase of 13 W/m^, of which approx 9 are from climate feedbacks. That means 28.5% of the direct increase is due to CO2, and the rest to feedbacks which is a lower forcing to feedback ratio than exists in the current data (33%). That the balance is essentially unchanged, therefore, is at least partly due to the small (<10%) incremental increase in the total greenhouse effect.

There is a way to show how the temperature-activated Arrhenius rate laws will show the constrained positive feedback. This leads to defined set-points in temperature given an increase in the CO2 “control knob”

Isn’t there an old joke about taking a physicist to the track to pick a pony? Something about spherical horses I believe.

Why do the most important factors always get ignored in these discussions? Which are the radiation absorbed by the Ocean and the the subsequent evaporation. Atmospheric radiation and changes within the atmosphere (Forcing’s) are a rounding error in the energy budget.

The oceans absorption of SW radiation and subsequent surface evaporation and radiation rate is the real Greenhouse Effect. 22˚ surface temperature and 5.5˚ average temperature which unsurprisingly is Kirchhoff’s S-B solution.

I know the physics can get messy, but that is where the fun is. I love pointing out that that the clocks in satellites actually run faster than surface clocks, despite going 25 thousand miles an hour, something to do with the gravity well I think. Oh and while I am on it, maybe just maybe G isn’t a precise constant? Could it be a wave and we are measuring different amplitudes?

The oceans absorption of SW radiation and subsequent surface evaporation and radiation rate is the real Greenhouse Effect. 22˚ surface temperature and 5.5˚ average temperature which unsurprisingly is Kirchhoff’s S-B solution.

What?

I love pointing out that that the clocks in satellites actually run faster than surface clocks, despite going 25 thousand miles an hour, something to do with the gravity well I think.

Actually Special Relativity means that clocks in the satellites that are moving very fast relative to the ground actually run slower than clocks on the ground. General Relativity tells us that clocks deeper in the gravitational well (on the ground) run slower than clocks less deep in the well (on satellites). I think Special Relativity wins with satellite clocks and they ultimately run slower than clocks on the ground.

Standard joke about physicists and spherical animals, which allows dismissal of physicists and their findings.

Followed by cherry picked facts which are assumed to result in desired conclusion without being modelled, without taking into account any complexity, and solely justified by segueing the afore mentioned dismissal of physicists into a dismissal of physics.

Were there no ocean surface to evaporate water from, indeed that would change things greatly. But while the evaporation is very real, what the GHGs do in the atmosphere is no less a part of the greenhouse effect. IOW it’s all real, and all accounted for. FWIW, note that the GHE has operated without (much) water vapor, i.e. in the early stage of transitions out of icehouse conditions.

Why are there no jokes about physicists and oblately spheroidal planets?

Tom and ATTP, The cherry picking is the result of my measurements and observations off the side of my sail boat. I have seen the surface temperature stay the same for up to a couple of weeks at a time, no diurnal variation at all. The temperature variation occurs beneath the surface where it is unaffected by changes in atmospheric radiation.

What does cause temperature changes is cloud coverage or lack thereof during the day and changes in wind speed (through mixing and evaporation). I have made hundreds of observations throughout the tropic and subtropic areas of the Bahamas and Caribbean and anyone with an IR gun can easily reproduce them.

What I haven’t seen is changes in cloud coverage affecting the surface temperature, even though my IR gun indicates that clouds are much warmer than clear sky.

Steve, if there were no oceans and water vapor in the atmosphere it would be equivalent to a high altitude desert correct? With very hot days and very cold nights, kind of like Mars wouldn’t you say?

Our world is much warmer due almost entirely to the Ocean and water vapor in the atmosphere. Yes an atmosphere with CO2 is warmer than an atmosphere without it, but CO2 isn’t the climate driver, H20 is.

The reason there are no jokes about physicists and oblately spheroidal planets is that physicists turn them into dwarfs and it is no longer PC to make fun of them.

“Largest single factor” and “driver” aren’t synonymous, Genghis. Change the CO2 amount and water vapor follows. Change the water vapor amount without changing CO2 first and… oops, can’t really do that.

Steve, the CO2 amount is irrelevant. CO2 is transparent to SW radiation so it doesn’t restrict SW radiation from entering the Ocean and the Ocean surface temperature doesn’t respond to changes in LW Atmospheric radiation.

What the Ocean surface temperature does respond to (besides wind levels) is whether SW radiation is blocked by clouds or not.

CO2 isn’t even a bit player in the ocean heat /loss drama. Where there is little or no H20 in the air like over Antartica or extreme deserts CO2 does create a little warming, but to try and claim that it is the driver of the Global Climate is absurd.

“Prior to the increase in anthropogenic CO2, the atmospheric CO2 concentration was about 280ppm. This would contribute a radiative forcing of about 30Wm-2, so about 20% of the overall [33K] greenhouse effect.”

Well then, taking this assumption at face value, in 1850 CO2 was responsible for about 6.44C warming above 255K equilibrium temperature [32.2C * 0.2], and CO2 responsible for about 6.6C warming now [33C * 0.2]. Thus, a ~43% increase in CO2 allegedly responsible for 0.16C warming, about a order of magnitude less than claimed.

The water temperatures show no more than 0.6 F (0.33 C) variation in temperature with hourly measurements over five days (Oct 7th-12th). They vary around a temperature of approximately 83.25 F (28.5 C). In contrast air temperatures show up to 11 F (6.1 C) variation around approximately 64 F (17.8 C), although on most days the diurnal cycle is about 1-2 F (.55-1.1 C).

I’ll note that I am not seeing anything that allows me to interpret your “22˚ surface temperature and 5.5˚ average temperature…” here, which remain dissociated numbers.

What I am also not seeing in the water temperature data is any appreciable diurnal cycle. The diurnal cycle rises from about 12:00 GMT to reach a peak around 16:00-18:00 GMT, and is fairly consistent. Over the same time period, only one rise in temperatures starts at 12:00 for GMT, with two following that by several hours, one preceding it by the same amount, and one showing a sharp fall on a day when nothing is out of the ordinary in the air surface temperatures. Your theory that the driver of surface temperatures is the ocean’ absorption of SW radiation with atmospheric forcings being “rounding errors” does not sit well with this data. If that were the case, we would at least expect to see a strong diurnal cycle in the data.

Even when awake I don’t expect them to be watching all the time, Willard. The comment was for their next appearance, whenever that is. If you’re implying that the suggestion is redundant, hopefully so.

Tom Curtis: “what you are telling us is that you are basing your theory on purely local observations from latitudes that are noted for their small temperature variations,”

I agree, my tiny set of observations and experimental constraints are obviously inadequate to base a theory on maybe even a hypothesis. They are enough however to cause me to question certain assumptions I had previously made.
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“The water temperatures show no more than 0.6 F (0.33 C) variation in temperature with hourly measurements over five days (Oct 7th-12th). ”

Buoy surface data (it measures the temperature a foot or so below the surface) is not the same as the thermal skin layer which is what I am referring to and I would be willing to bet that the thermal skin layer temperature at that buoys location was invariant at the time, as in zero temperature change.
*******

“I’ll note that I am not seeing anything that allows me to interpret your “22˚ surface temperature and 5.5˚ average temperature…” here, which remain dissociated numbers.”

I collected those numbers from various ocean data sheets who are in general agreement. One point I am trying to make with those temperatures is that the average ocean surface temperature (one foot below actually) is around 7˚ warmer than than the average atmospheric surface temperature (6 feet above the ground). It is the Ocean Surface that is the global temperature driver.

The second point is that a naive use of the S-B equation where emissivity=absorptivity of solar insolation yields a black body temperature of 5.5˚, which is curiously close to the average temperature of the entire ocean.

I am inferring from the above that the earths global temperature is very close to equilibrium.

*********

“What I am also not seeing in the water temperature data is any appreciable diurnal cycle. The diurnal cycle rises from about 12:00 GMT to reach a peak around 16:00-18:00 GMT, and is fairly consistent. Over the same time period, only one rise in temperatures starts at 12:00 for GMT, with two following that by several hours, one preceding it by the same amount, and one showing a sharp fall on a day when nothing is out of the ordinary in the air surface temperatures. Your theory that the driver of surface temperatures is the ocean’ absorption of SW radiation with atmospheric forcings being “rounding errors” does not sit well with this data. If that were the case, we would at least expect to see a strong diurnal cycle in the data.”

First of all to reiterate, the data you are using is subsurface temperatures which clearly warm and cool in any typical day, via SW warming and cooling from the surface via evaporation and LW radiation. The air temperature above the surface also warms and cools with the diurnal cycle.

My interpretation of the above data (my data that under certain conditions the surface temperature doesn’t change) is that the surface LW radiation is constant. That is what my IR gun is reading. And that changes in evaporation keep the surface temperature the same, very much like a boiling point.

Another point I should make is that the average surface temperature almost perfectly corresponds to the length of day with about a 2 to 3 month lag depending on Latitude.

Sorry, another point to make is that wind speed changes do make big temperature changes via mixing and evaporation changes.

Thank you for the reference, I read them a while back, and Nick’s stuff too. I think you are referring to the temperature gradient changes just below the surface?

What I measured was a layer of warm water just below the surface that expanded during the day and shrunk during the night. This warm layer was typically the same temperature from top to bottom the only thing that changed was the thickness.

If the Warm layer shrunk to nothing the thermal surface layer would follow suite and decline in temperature as well. Wind could also destroy the warm layer.

What is really interesting, is that with stable trade winds and waves the thermal skin layer temperature is remarkably stable day or night, with no detectable warm layer under the surface, other than the fact that the water temperature just below the surface is always warmer than the surface temperature.

Genghis, a genuine skeptic, who is not himself expert in a complex scientific subject like climate, acknowledges that there are actual experts who know much more about the subject than he does. Rather than pretending to know things you don’t, you could try educating yourself, starting with a good textbook. I recommend Global Warming: Understanding the Forecast, by David Archer.

“Isn’t there a hysteresis effect here? If at an earlier time the atmospheric concentration of CO2 was much greater than 280ppm – enough to warm the planet and increase the atmospheric concentration of water vapour, etc. to get a >33 degree increase in temperature – then when the CO2 level dropped back to 280ppm, the water vapour would still be at a high concentration, maintaining much of the temperature increase. In other words, what I’m trying to ask is – is it correct to consider all the 100W/m2 as a feedback to the 280ppm concentration of CO2?”

Water vapor concentration follows temperature almost instantly. Consider how thunderstorms form when temperature drops at night, or for a slightly longer term feedback, how winter humidity is lower than summer humidity (absolute, not relative). For that matter go look up the definition of relative humidity.

“…what would the radiative influence of the other factors be if we were 33 degrees cooler…”

A good point that Pierrehumbert makes in his textbook is that it’s only the CO2 which keeps water vapor in a vapor state. Without the CO2, most water vapor would snow out of the atmosphere, and all the snow/ice would, by the ice-albedo effect, cool the planet even further.

He writes (pg 271):
“One sometimes hears it remarked cavalierly that water vapor is the ‘most important’ greenhouse gas in the Earth’s atmosphere. The misleading nature of such statements can be inferred directly from Fig 4.31…. If water vapor were the only greenhouse gas in the Earth’s atmosphere, the temperature would be a chilly 268 K, and that’s even before taking ice-albedo feedback into account, which would most likely cause the Earth to fall into a frigid Snowball state…. With regard to Earth’s habitability, it takes two to tango.”

The numbers are meaningless unless you can cite the sources, and for those you collected yourself, specify time and location of collection, and instruments used (including how calibrated).

“The second point is that a naive use of the S-B equation where emissivity=absorptivity of solar insolation yields a black body temperature of 5.5˚, which is curiously close to the average temperature of the entire ocean.”

Hah! So 278.8 K raised to the fourth power, them multiplied by the Stefan-Boltzmann constant and then by 0.7 yields 239.8 W/m^2 which is approximately equal to the solar insolation of 1361 W/m^2 averaged over the Earth’s surface (ie, divided by 4) and multiplied by 1-albedo (=0.7), or 238.2 W/m^2. Very good. And from this we deduce that the emissivity of water in the visible spectrum is approximately equal to the emissivity of water in the IR spectrum.

Very good of you to form a theory and from it deduce simple, testable hypotheses. You did do that, didn’t you?

Yes, ok. Genghis, you’re welcome to comment but we don’t want lengthy arguments that deny the greenhouse effect. This is mainstream science and if you have an alternative theory, the best thing to do is to submit it to a scientific journal for publication.

David,
Thanks, that is a good point. The Lacis paper that Tom mentions in an earlier comment illustrates that too, I think. TBH, I wasn’t entirely sure about what water vapour would do in the absence of CO2, so I’ve learned something here.

Hockey Schtick,
I’ve let you comment through, but am not keen on promoting denier themes here. You have it the wrong way around. We’re confident that 3.7Wm-2 will produce 1 degree of warming. Anthropogenic forcings are about 2Wm-2 today, so are associated with around 0.5 – 0.6 degrees of warming. If you’ve read some of the comments, you’ll note that the greenhouse effect is consistent with an ECS of 3 degrees. Hence, it is maybe a little surprising that we’ve only warmed by around 0.9 degrees. However, we haven’t reached equilibrium, so it’s not inconsistent. We’re in a transient state, not an equilibrium state. However, the greenhouse effect does appear inconsistent with the low climate sensitivities estimated by Lewis & Curry.

In the defence of greenhouse effect you easily support assumptions about forcings and sensitivity that have to be reconsidered. A new paper tells us that Down LW radiation is contributing less to warming of oceans.
“The physics behind the model is based on the established fact that the oceans are opaque to long wave GHG energy but are very transparent to short wave solar energy. This implies that GHG energy is returned to the atmosphere and space very quickly as latent heat of evaporation while solar energy is effectively absorbed to a depth of many meters with consequent delays in equilibrium at the Top of the Atmosphere (TOA) are likely to be considerably faster, on average, for a change in GHG forcing than for a similar change in solar forcing. A crude forcings model has been developed that matches almost perfectly (R2 = 0.89) the National Oceanic and Atmospheric Administration (NOAA) temperature series from 1880 to 2010.
It is concluded, by implication that the efficacy of a GHG forcing is likely to be considerably lower than the efficacy of a similar sized solar forcing. ”
R. A. Irvine: A Comparison Of The Efficacy Of Greenhouse Gas Forcing And Solar Forcing

nobodyknows,
I’ll have a look at that, but technically it’s a book chapter, not a peer-reviewed paper. My understanding is that we’d expect our climate to respond the same to changes in anthropogenic forcings as to changes in solar forcings. If fact, it’s quite hard to see how it could do anything else.

And Korea comes marching on —
“By analyzing a millennium simulation (the period of 1000–1990 AD) of a global climate model and global climate proxy network dataset, we estimate the contribution of solar and greenhouse gas forcings on the increase in GMST during the present warm period (1891–1990 AD). Linear regression analysis reveals that both solar and greenhouse gas forcing considerably explain the increase in global mean temperature during the present warm period, respectively, in the global climate model. Using the global climate proxy network dataset, on the other hand, statistical approach suggests that the contribution of greenhouse gas forcing is slightly larger than that of solar forcing to the increase in global mean temperature during the present warm period. Overall, our result indicates that the solar forcing as well as the anthropogenic greenhouse gas forcing plays an important role to increase the global mean temperature during the present warm period.”
Contributions of solar and greenhouse gases forcing during the present warm period
Hyung-Gyu Lim, Sang-Wook Yeh, Ji-Won Kim, Rokjin Park, Chang-Keun Song

I’ve pondered how the climate would respond to CO2 forcings compared to solar forcings. The responses seem largely similar in both cases, but of course scientists have studied the small differences for years.

A good introduction is section 2.8.5 of the 2007 IPCC report. Each radiative forcing in figure 2.20 has an estimated climate efficacy, suggesting that solar forcings have a slightly lower climate sensitivity than CO2 forcings. Figure 2.19 cites seven studies showing that solar forcings have a climate sensitivity that’s ~70% to ~100% as large as CO2 forcings.

More recent research like Schaller et al. 2013 and Kleidon and Renner 2013 models different changes in water vapor and the water cycle during warming caused by sunlight or CO2. Huneeus et al. 2013 finds that the climate sensitivity parameter is independent of the forcing (when measured as an effective radiative forcing).

ATTP, it is not even a book chapter, but one of a collection of papers presented at a conference on heat transfer. You will find it promoted all the expected dubious places. Irvine himself even wrote a guest post at WUWT.

That Korean paper I would need to check further (if I actually was interested), but looks very much like mathturbation similar to what we have seen from many others. May well be the reason it was published in a minor journal (IF 1.2)

nk, just because you are ignorant is no reason to slander us all with your name.

On this occasion, you choose to reemphasise your ignorance by quoting (without citation) Lim et al (2014). In that paper, Lim et al:
1) Demonstrate their model fails to reproduce millennial temperatures due to a massive discrepancy (from 0.4-0.8 C) in the LIA (see fig 1), but claim close enough is good enough because they get a correlation of 0.6 and don’t quote RMSE;

2) From this failed model, they calculate a climate response of 0.086 K/(W/M^2) to solar forcing in the medieval, and 0.156 K/(W/m^2) in the modern period, attributing the difference to the greenhouse forcing in the modern period. They hence derive an approximately 50/50 split of contribution which seems reasonable given the approx 0.6 W change in forcing over the relevant period for both, until you notice that:

3) They calculate solar forcing as change in TOA insolation without any albedo adjustment. That means they are overestimating solar forcing by a factor of 5.7 and the contribution, and that their ERIK model overstates solar forcing by the same factor (something quite visible in their model reconstruction the last millennium’s warming).

4) And despite massively overstating the solar contribution, they still need (in 2013) to restrict their discussion to the warming between 1890 and 1990 to obtain their result which can be cast by the ill informed as contradicting the IPCC claim about warming between 1950 and 2010. With recent declining solar forcing and ongoing rise in greenhouse forcing, extending their analysis by an extra twenty years would have greatly reduced their already massively inflated solar contribution.

I’m sorry, their blunder on solar forcing puts this paper in the category of “I can’t believe it got past peer review”, while reinforcing that your name certainly explains your state of knowledge, if nobody elses.

Out of interest, here is fig 5.8 from WG1 or AR5, comparing model simulations with reconstructed temperatures over the last millenium. The comparison shows very favourably relative to that in Lim et al’s fig 1, even with their “strong solar variability” simulations. Of course, by strong solar variability, they do not mean amplified forcings by a factor of 5.7 😉

ATTP says “You have it the wrong way around. We’re confident that 3.7Wm-2 will produce 1 degree of warming. Anthropogenic forcings are about 2Wm-2 today, so are associated with around 0.5 – 0.6 degrees of warming. If you’ve read some of the comments, you’ll note that the greenhouse effect is consistent with an ECS of 3 degrees. Hence, it is maybe a little surprising that we’ve only warmed by around 0.9 degrees. However, we haven’t reached equilibrium, so it’s not inconsistent.”

Per Otto et al, ECS is only about 1.3*TCR, thus as stated above, “in 1850 CO2 was responsible for about 6.44C warming above 255K equilibrium temperature [32.2C * 0.2], and CO2 responsible for about 6.6C warming now [33C * 0.2]. Thus, a ~43% increase in CO2 allegedly responsible for 0.16C warming, about a order of magnitude less than claimed.” from which can be derived using the conventional assumptions that TCR is 0.25C to a doubling of CO2 levels, and per Otto et al, ECS would thus be about ~ 1.3*0.25 = 0.325C

“We’re confident that 3.7Wm-2 will produce 1 degree of warming.”

Assuming this is true, for the 33K GHE, 33*3.7W/m2 = 122.1 W/m2 total greenhouse forcing, of which you said 30W/m2 is from CO2, so 30/122.1 = 25% of the 33K GHE from CO2 alone, even more than the 20% stated above. Using 25% instead of 20% in the above calculation has the effect of reducing TCR to 0.19C to a doubling of CO2 levels, and per Otto et al, ECS would thus be about ~ 1.3*0.19 = 0.25C

Your error is essentially that you’re comparing a transient temperature change with an equilibrium temperature change. We haven’t reached equilibrium yet. Even the IPCC best estimate for the TCR of 1.8 degrees, suggests that the anthropogenic forcings dominate over the feedbacks at the time of doubling. An ECS of around 3 degrees, however, suggests that once equilibrium is reached, the anthropogenic forcings contribute around one-third of the radiative influence. The Otto et al. ECS best estimate was around 2 degrees with a 95% range from 1.2 to 3.9 degrees, so is consistent with the greenhouse effect having an ECS of about 3 degrees.

As Tom Curtis points out above, my basic numbers were also slightly wrong. A better way to look at this is in terms of the sensitivity to the CO2 forcing. In other words, CO2 alone produces a change in forcing of about 32Wm-2. This gives a climate sensitivity of Wm-2K-1. The equilibrium sensitivity is then $ECS = 3.44/0.97 = 3.5$ K.

In fact your argument is a little odd. You seem to be using the greenhouse effect to argue that today the CO2 contribution to the warming is low and therefore that the feedbacks are large.

Do you disagree with this finding of Otto et al and/or Willis’ interpretation?

“In fact your argument is a little odd. You seem to be using the greenhouse effect to argue that today the CO2 contribution to the warming is low and therefore that the feedbacks are large.”

I’m simply using the assumptions you stated in this post, i.e. the total GHE is 33K and CO2 is responsible for ~20% of that, to show that these assumptions are incompatible with high TCR, and thus also with a high ECS to CO2 [given the findings of Otto et al that ECS ~= 130% of TCR].

1) Otto et al do not assert that ECS is 1.3 times TCR. They found an ECS 1.5 times greater than the TCR they found. However, regardless of the ratio found, if you disagree with their estimate of TCR, you are not entitled to use their ratio to determine ECS from TCR.

2) Your calculation of the temperature effect of the 280 ppmv of CO2 in the atmosphere c1850 assumes there are no feedbacks. Your scaling of that alleged contribution to account for a CO2 contribution to the increased warming therefore also assumes no feedbacks. Assuming by definition that warming due to CO2 cannot have any feedbacks is a mistake. Better, it is a massive blunder showing that you want to achieve by false assumptions what you cannot achieve by honest argument.

3) As noted above, if you do not assume a priori that CO2 can have no feedbacks, the impact of the CO2 present in the atmosphere c1850 is greater than 35 C. (Greater than because the 35 C shown by Lacis et al assumes no increase in ice sheet or glacial surface area, and therefore underestimates the effect.)

4) In addition to the above mistakes, your calculations of relevant values is in error (due primarily to using the wrong equations) as is shown by your finding an ECS of 0.25 C for a doubling of CO2 when the no feedback response is approx 1.1 C. That is, by assuming no feedbacks you have deduced a massive negative feedback and thereby contradicted yourself due to nonsense equations. (I cannot spell out the errors of the equations in detail because you do not specify them in sufficient detail.)

If you had specified the equations you used in enough detail to actually follow the operations, it would be trivial (and tedious) to point out 5 or 6 additional errors.

Seriously, normally you only see comments as silly as yours in a comedy routine.

You said;
“Hah! So 278.8 K raised to the fourth power, them multiplied by the Stefan-Boltzmann constant and then by 0.7 yields 239.8 W/m^2 which is approximately equal to the solar insolation of 1361 W/m^2 averaged over the Earth’s surface (ie, divided by 4) and multiplied by 1-albedo (=0.7), or 238.2 W/m^2. Very good.k”

From your reference;
“Water is a non-black-body emitter with an emissivity slightly less than one,” It provides the actual emission (temperature dependent) between .95 and .99.

I used ‘one’ for the emissivity rather than the .7 you used in your calculation I also use ‘one’ for the absorptivity rather than .7 based on Kirchhoff’s law.

Yes I know that the oceans albedo is actually around .05 (.95) but as far as I can tell the oceans emissivity and absorptivity is pretty close, and I like multiplying by one 🙂 Albedo is primarily a land, Ice and cloud phenomenon which is where you get your .7 number from.

That is my point though, the ocean radiation and emission physics are markedly different than land physics because the primary processes aren’t the same. On land the surface absorbs and emits, on the ocean the surface evaporates and emits, the absorption takes place below the surface.

2. “Your calculation of the temperature effect of the 280 ppmv of CO2 in the atmosphere c1850 assumes there are no feedbacks.”

No, it does not. The calculation is based upon the ATTP assumptions as stated in this post, i.e. the total greenhouse effect [after all feedbacks] is currently about 33K [and about 0.7-0.8C less during preindustrial times IF one assumes all warming from the GHE], and that CO2 contributes about 20% of the total greenhouse effect [after all feedbacks].

3. “As noted above, if you do not assume a priori that CO2 can have no feedbacks, the impact of the CO2 present in the atmosphere c1850 is greater than 35 C”

Firstly, as stated above, I did not assume no feedbacks. The 33K greenhouse effect above the 255K equilibrium temp as conventionally calculated IS after all feedbacks. Now, remarkably, you are stating the greenhouse effect of CO2 alone is >35C. Pray tell, what do you claim is the total greenhouse effect in K and W/m2 with and without feedbacks? Please provide a link to the calculations.

And please note you are implying that the feedbacks are highly negative, you do realize that, right?

4) Once again, the calculations are AFTER feedbacks assuming AFTER feedbacks the total GHE is 33K, and that CO2 AFTER feedbacks contributes 20-25% of that. Here’s the calculations:

Assuming CO2 AFTER feedbacks contributes 25% of the 33K GHE AFTER feedbacks:

HS,
As Tom points out, Otto et al. actually find that the ratio of their best estimate for TCR and best estimate for ECS is 150%, not 130%. Also, my 20% is probably too low as you’ve already pointed out. It’s probably more like 25%.

Also, the point of my post is really that the GHE is not really consistent with an ECS as low as 2 degrees (i.e., in which CO2 contributes half of the radiative effect at equilibrium). Bear in mind that the Otto et al. ECS estimate is both very sensitive to the system heat uptake rate which may well be underestimated and their result is consistent with an ECS above 3 degrees (i.e., their range is 1.2 to 3.9 degrees).

HS,
I don’t know why you’re being so precise, but if you accept that CO2 produces about 8 degrees of GHE warming and about one-quarter of the radiative influence, then that’s 8 degrees per 32Wm-2, or 4Wm-2 per degree (a little higher than the accepted 3.7Wm-2 per degree, but let’s not quibble). Anthropogenic forcings today are thought to be 2Wm-2, therefore producing (by your own argument) 0.5 degrees of warming. You’re essentially arguing that an increase in forcing of 3.7Wm-2 produces much less than 1 degree of warming. Given that that is fundamentally part of the Otto et al. calculation, it’s inconsistent of you to use that calculation to argue as you have.

Look, I know your position wrt to the greenhouse effect and have spent a good deal of my time discussing it with you in the past. You clearly hold a minority position that is in disagreement with a vast majority of actual experts. I know that you get upset when people suggest you deny the greenhouse effect, but that appears to be because you’ve called your process the greenhouse effect despite it being completely at odds with the mainstream explanation for the greenhouse effect (this seems a little like a government redefining serious crimes so they can claim that serious crimes have reduced). You’re more than welcome to hold this minority position, but I’ve spent more than enough of my free time discussing it with you and don’t particularly fancy moderating a comment stream where you promote it here.

ATTP: I am not even discussing my argument here why the entire ~33K “greenhouse effect” is entirely explainable on the basis of the barometric formulae, atmospheric mass, gravity, heat capacity, lapse rate, independent of CO2 levels. I’m not even going there in these comments, since you have no interest in discussing that concept any further. Thank you for noting that I by no means deny a 33K “greenhouse effect,” but disagree on the primary cause.

Thus, for discussion purposes, I am simply starting with the assumption that what you stated above is correct, i.e. the “greenhouse effect” is about 33K at present after all feedbacks, and CO2 alone is responsible for 20-25% of that 33K greenhouse effect, after all feedbacks. Have I stated your position correctly?

I then show from these two assumptions alone that the TCR has to be much lower than assumed [and hence ECS = ~1.3-1.5 * TCR] per the calculations above.

Apparently Tom Curtis has a vastly different position that the GHE attributable to CO2 alone is >35C before feedbacks. Do you agree with that assertion?

I don’t want to misquote anyone, so would you and Tom Curtis please clarify for the record what your best estimate is of the total GHE before and after all feedbacks, and what your best estimate is of the CO2-only GHE contribution before and after all feedbacks. Please state both in terms of W/m2 forcing at the surface and degrees K at the surface.

Thus, for discussion purposes, I am simply starting with the assumption that what you stated above is correct, i.e. the “greenhouse effect” is about 33K at present after all feedbacks, and CO2 alone is responsible for 20-25% of that 33K greenhouse effect, after all feedbacks. Have I stated your position correctly?

Yes, that is broadly my position with respect to the GHE, although there are other papers that put it at closer to one-third than a quarter.

I then show from these two assumptions alone that the TCR has to be much lower than assumed [and hence ECS = ~1.3-1.5 * TCR] per the calculations above.

No, that isn’t what you’ve done. The first step of your calculation accepts that 32Wm-2 is associated with 8 degrees of warming, or about 4Wm-2 per degree – close enough to what is commonly accepted. You then try to do the following

The problem is as follows. We’re not yet in equilibrium. Even Otto et al. is consistent with an ECS of 3.9 degrees. Lets redo the calculation with that as the ECS. Once we’ve equilibrated, the overall change in temperature will be 36.9 degrees (33 + 3.9). Now multiply that by 0.25 and subtract 33/4. You get 0.975 degrees. In other words, CO2 has contributed about 1 degree of our recent warming once we’ve equilibrated.

Of course, if the ECS is not as high as 3.9 degrees, then it would be lower, but that’s kind of the point of this post. Most lines of evidence support an ECS of around 3 degrees. Otto et als. (and Lewis & Curry’s) best estimates are on the low side. The ranges overlap, so I’m not suggesting that they’re wrong. I’m simply pointing out that there are other ways to estimate the climate sensitivity and it suggests values greater than that suggested by Otto et al. and Lewis and Curry.

1) To determine the ratio of ECS/TCR from Otto et al, I consulted Otto et al. I do not care what Willis(?) said at an unknown website.

2) The study (Schmidt et al 2010) that shows CO2 produces 20% of the total greenhouse effect does not allow the atmospheric components such as water vapour and cloud cover to adjust as the result of the removal or addition of CO2. Therefore it has no feedbacks. Your declaring otherwise on your own authority is meaningless.

3) I have already linked to Lacis et al 2010 above. Further, if the removal of 280 ppmv of CO2 (a negative forcing) causes a greater negative temperature response than predicted from the change of forcing alone and without feedbacks, that is a positive feedback. Negative feedbacks work against the sign of the forcing, positive feedbacks with it.

There is literally no point in discussing your detailed calculations until you acknowledge the most fundamental point, ie, that the 20% of total greenhouse effect is a no-feedback figure.

“We quantify the impact of each individual absorber in the total effect by examining the net amount of long-wave radiation absorbed in the atmosphere (G, global annual mean surface upwelling LW minus the TOA LW upwelling flux) [Raval and Ramanathan, 1989; Stephens and Greenwald, 1991]. This is zero in the absence of any long-wave absorbers, and around 155 W/m^2 in the present-day atmosphere [Kiehl and Trenberth, 1997]. This reduction in outgoing LW flux drives the 33◦C greenhouse effect defined above, and is an easier diagnostic to work with. We therefore use the percentage change in the LW flux reduction as our metric for the greenhouse effect throughout this paper. All percentages can easily be converted to W/m^2 by multiplying by 155. There is a connection between our metric and the oft-used ’no-feedback’ temperature (i.e. the surface temperature change that re-equilibriate the top-of-atmosphere (TOA) radiation assuming a constant lapse rate and that all other constituents remain constant) [Hansen et al., 1984, 1988], but the relationship is not linear, nor constant across absorbers.

And later:

“It is in part due to these non-linearities combined with associated feedbacks that the attribution calculations are not directly useful for determining climate sensitivity. For instance, one can’t simply take the attribution to CO2 of the total greenhouse effect (20% of 33◦C) and project that onto a 2×CO2 scenario. That would exaggerate the no-feedback impact of the extra CO2 while ignoring the role of feedbacks that might change the water vapour and clouds. In GISS ModelE, the Charney sensitivity is 2.7◦C for a doubling of CO2 (or ∼0.7 ◦C/(W/m^2)) [Schmidt et al., 2006].

Based on that linear relationship, one simple way to calculate the no feedback response is 3.7*33/155 = 0.8 C per doubling of CO2. That is better than the formula they explicitly reject, but still inaccurate. Due to the non-linearities, the no feedback response is actually 1C per doubling (as calculated using algebra from a zero dimensional model) to 1.2 C per doubling (based on detailed calculation using Global Circulation Models).

Later still Schmidt et al write:

“At the 2×CO2 equilibrium, the global mean increase in G, the total greenhouse effect, is around 20 W/m^2, significantly larger than the 4 W/m^2 initial forcing and demonstrating the overall affect of the LW feedbacks is positive (in this model). That is, the extra net absorption by CO2 has been amplified by the response of water vapour and clouds to the initial forcing. The 20 W/m^2 greenhouse effect enhancement is associated with a 15 W/m^2 extra emission from the surface (since the planet has warmed by 2.7◦C) and a 5 W/m^2 reduction in outgoing LW that balances a 1.5% increase in planetary albedo (due to increased cloud cover, a negative (SW) feedback).

That 20 W/m^2 is the “with feedback” response, so if you want to apply a simple linear formula, you then get a temperature response of 20*33/155 = 4.26 C. Again, however, we know the simple linear calculations are an error, and the actual response is 2.7 C, at least in that model.

“Apparently Tom Curtis has a vastly different position that the GHE attributable to CO2 alone is >35C before feedbacks. Do you agree with that assertion?”

What I actually wrote:

“As noted above, if you do not assume a priori that CO2 can have no feedbacks, the impact of the CO2 present in the atmosphere c1850 is greater than 35 C. (Greater than because the 35 C shown by Lacis et al assumes no increase in ice sheet or glacial surface area, and therefore underestimates the effect.)”

(Emphasis added.)

Normally I get quite annoyed with people misrepresenting me, but given that HS has already misrepresented Otto et al, Schmidt et al, and Lacis et al, in this case I think it just places me in elevated company 🙂

HS, the “total greenhouse effect” is the difference between upward IR radiation at the surface and upward IR radiation to space. It is meaningless to quote it “at the surface” as it is the difference between values at the surface and TOA. It is likewise meaningless to quote the it “before and after all feedbacks” because it necessarily includes any feedbacks as distinct components (and hence quoting the value of just one component excludes those feedbacks). Finally, forcings are by definition determined at the TOA (or more properly top of tropopause) and hence quote surface values is rather futile.

For what it is worth, the change in surface upward IR flux is to a first approximation given by the Stefan-Boltzmann law and the change in equilibrium temperature. The change in TOA upward IR flux is to a reasonable approximation zero because we are comparing equilibrium conditions. There will be small differences due to small differences in IR flux needed to balance any small differences in SW flux, but the amount of those changes us abstruse and uncertain.

The best estimate of the equilibrium change in surface temperature for a doubling of CO2 is given by the most recent IPCC report.

“No, that isn’t what you’ve done. The first step of your calculation accepts that 32Wm-2 is associated with 8 degrees of warming, or about 4Wm-2 per degree – close enough to what is commonly accepted.”

I make no such assumption nor assume any such circular reasoning about W/m2 net forcing at the surface/TOA.

The only assumptions made are:

1. The total GHE after all feedbacks is presently ~33K, as per the usual calculations found in a million places on the internet.
2. Global temperatures have risen per HADCRUT3 ~0.8C since 1850/pre-industrial times
3. CO2 contributes ~25% of the total greenhouse forcing

from which TCR is determined using these 3 assumptions alone to be ~0.19C

From what I gather from several of your comments above, you don’t have a major problem with these assumptions so far, but where you disagree is “The problem is as follows. We’re not yet in equilibrium…”

However,

1. Otto et al, based upon observations, finds ECS is only 1.3-1.5X higher than TCR. For purposes of discussion, I’ll use the 1.5X figure even though Willis disagrees [and I haven’t yet looked at the paper again to see who is right and whether it is 1.3X or 1.5X].
2. The modeled estimates of ECS greater than TCR are based upon unrealistic assumptions about CO2 lifetimes, positive feedbacks, etc., but I’m not even going to get into that. Better to use a paper such as Otto et al that determines ECS from observations, not models.

Thus, 0.19C * 1.5 = 0.285C ECS to doubled CO2

What the heck, let’s assume ECS is 300% higher than TCR:

0.19 * 3 = 0.57C ECS to doubled CO2.

Not too exciting, right?

I’m also trying to understand why Tom Curtis apparently disagrees about the total GHE being ~33K after all feedbacks, and CO2 contribution >35K before feedbacks. Any ideas?

Genghis, if you are not averaging over the Earth’s surface (and hence using the Earth’s bond albedo to determine reflectance), you need to do it surface by surface, cell by cell. That is, you need a GCM. Come back when you have published the description of your in the scientific literature, along with your preliminary results. Absent that your argument degenerates to “the scientists are wrong because I haven’t bothered do the calculations to show it”.

1.The total GHE after all feedbacks is presently ~33K, as per the usual calculations found in a million places on the internet.

Okay, I agree with that.

2. Global temperatures have risen per HADCRUT3 ~0.8C since 1850/pre-industrial times

Okay, fine.

3. CO2 contributes ~25% of the total greenhouse forcing

Only true at equilibrium, which is the issue with your calculation. To take it a step further. If Otto et al. is correct that the TCR is 1.35 degrees and that the ratio of ECS to TCR is 1.5, then it would be rather surprising as that would imply a smaller feedback factor today than is true for the GHE overall. That was kind of the point of the post.

Having said that, an ECS of 2 degrees is not ruled out by other analyses, it’s just on the low side of most other analyses.

HS,
Actually, you may have a point. It is, of course, possible that the aerosol forcing is bigger than we think and hence that the net anthropogenic forcing is smaller than we think. Consequently the anthropogenic-only warming will be smaller than we think, the feedback response is larger than we think, and the TCR and ECS are, consequently, larger and more in-line with other estimates.

I will let you in on a little secret that i am sure you already know, we don’t have the computing power or theories (or time) to model clouds, even Moores Law has succumbed lately. And no I am not saying the scientists are wrong, I am quite certain the Land Centric view is largely correct, over land. I think the oceans have been largely ignored for precisely the reason you gave above, we don’t have the data (or even the modeling) from the oceans we need. It is hard to say anything definitive, or even guess, without the data to back it up.

I could play games computing the total absorbed insolation by the oceans vs insolation absorbed and reflected by the land vs Latitude and total energy levels (something close to 90%) but I don’t think it would matter.

What I have is data that shows that atmospheric radiation changes don’t cause or correlate with ocean surface temperature changes.

“3. CO2 contributes ~25% of the total greenhouse forcing. Only true at equilibrium, which is the issue with your calculation.”

Why do you say that? Above you said CO2 is 20% of the present GHE, i.e. not at equilibrium.

Here’s the GISS Model E output that was used by Gavin and Andy in writing their 2010 paper on the GHE, including things Reto refers to in the model output as “a little puzzling,” and most of which they conveniently left out of that paper. This is from the NASA FOIA files:

The model claims an instantaneous effect of doubling CO2 at the tropopause of 4.54C, and an instantaneous effect of -24.C from removing all CO2, an instantaneous effect of removing all GHGs of 29C, which is close to the ~33K GHE, removing all aerosols only 2.7C, etc. etc.

And here’s an email between Andy & Gavin stating that the instantaneous effect of 380 ppm CO2 added to 0 ppm CO2 in the model is 7K of the total 33K GHE [i.e. 21% of the total GHE, just as you and I assumed above several times].

Thus, as I stated above, CO2 contributes 20-25% of the total instantaneous/transient sensitivity and my calculations above correct given the same assumptions of the GISS model E.

From that calculation of TCS, even if you use an unrealistic assumption that ECS = 300% of TCS, we still arrive at an unexciting, very low ECS.

Tom Curtis: please see the above email images from the GISS FOIA files which prove that your assertion above “The study (Schmidt et al 2010) that shows CO2 produces 20% of the total greenhouse effect does not allow the atmospheric components such as water vapour and cloud cover to adjust as the result of the removal or addition of CO2. Therefore it has no feedbacks. Your declaring otherwise on your own authority is meaningless.” is false and these emails clearly show all the model “experiments” that Gavin & Andy didn’t want to mention in their paper regarding the instantaneous effects on the GHE of the addition and subtraction of the various components in GISS model E and their instantaneous effects on the tropopause, including all the remaining feedbacks and forcings.

Why do you say that? Above you said CO2 is 20% of the present GHE, i.e. not at equilibrium.

No I didn’t. The GHE is, by definition, the equilibrium change. I was probably wrong about it being as low as 20%, but that’s rather beside the point.

From that calculation of TCS, even if you use an unrealistic assumption that ECS = 300% of TCS, we still arrive at an unexciting, very low ECS.

If the TCR is as Otto et al. suggest, then it doesn’t really matter how much is CO2 and how much is feedbacks. The TCR is the overall response to a doubling of CO2. If the ECS is 1.5 times the TCR, then that is the ECS. Also – as I’ve pointed out a number of times – your calculation results in a change in forcing of 3.7Wm-2 producing much less than 1 degree of warming. Most people accept that this is wrong. It’s also fundamentally part of the whole GHE calculation. You can’t use a calculation that assumes 3.7Wm-2 produces about 1 degree of warming to then argue that it produces much less than 1 degree of warming. It’s logically inconsistent.

Firstly allow me to correct above my comment about the GISS model E outputs – I missed the “W/m2” on the printout, so the above figures in that comment are the instantaneous W/m2 at the tropopause, not degrees C. Thus, according to GISS model E, the instantaneous effect of removing all 380 ppm CO2 is -23.29 W/m2, which using your assumption of 3.7 W/m2 per 1C surface warming, would instantly decrease T by ~6.3C [while including all other forcings and feedbacks], i.e. 19% of the 33K total non-equilibrium GHE at present and almost the same as Andy & Gavin claimed of 20% in their 2010 paper.

“Also – as I’ve pointed out a number of times – your calculation results in a change in forcing of 3.7Wm-2 producing much less than 1 degree of warming.”

The assumption of 3.7Wm-2 forcing at the TOA per doubling is exaggerated, as I am demonstrating with the GHE calcs above, which make no such assumptions of the net transient or equilibrium forcing in W/m2, and instead use the much more “robust” assumptions as outlined above.

The only assumptions made are:

1. The total GHE after all feedbacks is presently ~33K, which Andy & Gavin agree in the emails above is “the 33K total terrestrial greenhouse effect” now, not at equilibrium. This typical calculation of the 33K GHE at present does not assume equilibrium:

2. Global temperatures have risen per HADCRUT3 ~0.8C since 1850/pre-industrial times

3. CO2 contributes ~25% of the total greenhouse forcing, which Gavin and Andy claim in their paper is presently right now 20% of the total, non-equilibrium GHE, or 19% of the total, non-equilibrium GHE at present per the “experiments” of GISS model E in the emails above.

4. CO2 levels have increased ~43% since 1850 and the radiative effect is logarithmic

5. All temperature rise since 1850 is anthropogenic [obviously not true, but I’ll make that assumption for purposes of discussion, not making this assumption obviously lowers TCS even further]

That’s all of the assumptions necessary; it is therefore not necessary to make any dicey assumptions regarding the net transient or equilibrium forcing in W/m2 at the tropopause or the surface to determine the TCS from these “robust” assumptions. From there, even if one makes the assumption that ECS is 500% of TCS, we’re still shy of 1C ECS.

Well, I’ve stated my case several times now and we appear to just be going in circles with you claiming that I am assuming 3.7 W/m2 per 1C surface warming, but I am not, and I am further demonstrating why that assumption is flawed by the use of the much more “robust” assumptions.

HS, it becomes evident that you do not even know the definition of “Radiative Forcing”. The term “Radiative Forcing” is explicated by the IPCC using Fig 8.1:

“Figure 8.1 | Cartoon comparing (a) instantaneous RF, (b) RF, which allows stratospheric temperature to adjust, (c) flux change when the surface temperature is fixed over the whole Earth (a method of calculating ERF), (d) the ERF calculated allowing atmospheric and land temperature to adjust while ocean conditions are fixed and (e) the equilibrium response to the climate forcing agent. The methodology for calculation of each type of forcing is also outlined. DTo represents the land temperature response, while DTs is the full surface temperature response. (Updated from Hansen et al., 2005.)”

In this concept the two important concepts are “Radiative Forcing”, illustrated by Fig 8.1b, and which allows for stratospheric adjustment, and “instantaneous Radiative Forcing” illustrated by Fig 8.1a. If that is not clear enough for you, from the glossary we have the following definition:

“Radiative forcing Radiative forcing is the change in the net, downward minus upward, radiative flux (expressed in W m^–2) at the tropopause or top of atmosphere due to a change in an external driver of climate change, such as, for example, a change in the concentration of carbon dioxide or the output of the Sun. Sometimes internal drivers are still treated as forcings even though they result from the alteration in climate, for example aerosol or greenhouse gas changes in paleoclimates. The traditional radiative forcing is computed with all tropospheric properties held fixed at their unperturbed values, and after allowing for stratospheric temperatures, if perturbed, to readjust to radiative-dynamical equilibrium. Radiative forcing is called instantaneous if no change in stratospheric temperature is accounted for. The radiative forcing once rapid adjustments are accounted for is termed the effective radiative forcing. For the purposes of this report, radiative forcing is further defined as the change relative to the year 1750 and, unless otherwise noted, refers to a global and annual average value. Radiative forcing is not to be confused with cloud radiative forcing, which describes an unrelated measure of the impact of clouds on the radiative flux at the top of the atmosphere.”

(Second emphasis mine)

Given those definitions it is very plain that the two columns in the FOI document are columns for Instantaneous Radiative Forcing (“instantaneous radiative forcing”) and Radiative Forcing (“adjusted in stratosphere”) respectively, and that consequently neither of them represents a situation with feedbacks. In particular, the more the stratospheric adjustment involves no changes in IR active molecular concentrations (there being no seas or lakes in the stratosphere for water vapour to evaporate from, and water vapour being so minor a component of the stratosphere in any event) and that the adjustment consists almost entirely in the change of stratospheric temperature which occurs over a matter of days.

Beyond that, I cannot say. With characteristic obscurity you do not link to the full file of FOI documents so that we do not even know the date of the email nor the description of the the experiments, nor the model configuration. We cannot, therefore, determine the relationship between those figures and the figures reported in Schmidt et al. From the wording of the paper, they look like a preliminary exploration rather than the actual runs used for the paper, but absent the relevant documents, who knows.

Allow Eli to point out that 33 C for the greenhouse effect is an upper limit found for a non-rotating one sided planet. Arthur Smith went through the exercise in arXiv http://pubs.acs.org/doi/abs/10.1021/jp410749a but to get a more realistic value you have to model the heat capacity and albedo of the planet and its components.

Oh yeah, re Lacis and Gavin. If you magically disappear the CO2 and don’t wait for the water vapor to plunge due to decreased humidity, you get what he says. If you do it anyhow and wait a while you get iceball earth. It’s the difference btw TCO2S and ECO2S if Eli may coin an acronym.

Eli, not sure what “TCO2S” stands for, but in the single factor removal experiments, Gavin removed CO2 and held water vapour and clouds fixed. In the single factor addition experiment he added CO2 to an atmosphere with no greenhouse gases (including water vapour and clouds) and held water vapour and clouds (and other greenhouse gases) at zero. Neither can be called a transient response, and nor can either be called the CO2 effect with feedbacks, as HS wants to do. (I am suspecting his first initial is five letters in the alphabet too late.)

HS,
Let’s not continue this, but what you’re forgetting is that CO2 producing about 20-25% of the GHE is based on a doubling of CO2 (3.7 Wm-2) producing about 1 degree of warming. You’re therefore using something in which doubling CO2 produces 1 degree of warming to argue that it produces much less than 1 degree of warming – i.e., it is logically inconsistent. If doubling CO2 produces much less than 1 degree of warming, then CO2 would contribute much less than 20-25% of the GHE. You could then redo your calculation to show that CO2 produces much much less than 1 degree of warming, and you’d end up in an infinite loop.

Hey, thanks for the reference 🙂 Actually 33 C is a lower limit, not an upper limit for the magnitude of the greenhouse effect – the actual average temperature of Earth could be much lower than -18 C and still maintain the steady-state energy balance with incoming solar energy, with no GHE under conditions with a wide range of temperatures from one place to another.

Which relates to what I think is a confusing element in ATTP’s main article here and some responses in the discussion – repeated over and over again is the claim that doubling CO2 produces about “1.1 degree of warming by itself”, and I think that’s the basis for some of the numbers in the main post. The problem I have is with the “by itself”. By itself, all that CO2 does is change infrared radiation flows in the atmosphere, reducing outward radiation from the top of the atmosphere and increasing downward flow to the surface. Temperature change is ONE way in which our planet responds to this change in energy flows. The canonical Planck response (the “by itself” number) is calculated by assuming that the planet responds by changing in temperature by the same amount at every point on the planet (including throughout the oceans) and throughout the troposphere, to rebalance the energy flows, while leaving the specific composition and state of everything else fixed. That is, the “by itself” Planck response is an EQUILIBRIUM response assuming nothing but temperature changes. But we know that’s not what actually happens. First of all – because of heat flow into the oceans, the planet can stay OUT of equilibrium for a very long time, so equilibration to a steady state is not an immediate response at all. Also, a big part of what actually happens in this response involves changes in the water cycle – which happen simultaneously (at most a few weeks lag) with temperature changes. Keeping all the water content in the atmosphere exactly fixed while changing the temperature is a highly artificial construct, convenient perhaps for theoretical calculation, but bearing little resemblance to the actual physical system.

In particular, if we were looking at the response to a negative forcing, i.e. the temperature decreases, then anywhere relative humidity was at 100% before the response is calculated (which is the situation immediately above many water surfaces), the Planck response assumes a highly UNPHYSICAL situation with the atmosphere super-saturated with water vapor. That does not happen in the real world. A much closer approximation to reality would be to assume fixed relative humidity while changing the temperature as a starting point (models seem to indicate this is what happens anyway, as you’ve discussed in the Montford thread). Then the “by itself” response to doubling CO2 would be about 2.2 C, not 1.1 C. But again that’s an equilibrium response, what it takes to return to balance in energy flux. Transient responses along with cloud and ice changes complicate all that.

In any case, my point is simply that there’s nothing special about the 1.1 C number, other than that it’s very easy to calculate and irrefutable. It is based on an unphysical partitioning of the response and is not what happens in the real world at all.

In any case, my point is simply that there’s nothing special about the 1.1 C number, other than that it’s very easy to calculate and irrefutable. It is based on an unphysical partitioning of the response and is not what happens in the real world at all.

Comparing with hypothetical, and even impossible, cases can be done in many ways leading also to different quantitative outcomes. For that reason I prefer to consider the value of 33 C only as the real present (approximate) difference between the average surface temperature and the effective radiative temperature of the Earth with its atmosphere and clouds. That’s one way of measuring the strength of the GHE, and that way does not refer to anything hypothetical.

“Beyond that, I cannot say. With characteristic obscurity you do not link to the full file of FOI documents so that we do not even know the date of the email nor the description of the the experiments, nor the model configuration. We cannot, therefore, determine the relationship between those figures and the figures reported in Schmidt et al. From the wording of the paper, they look like a preliminary exploration rather than the actual runs used for the paper, but absent the relevant documents, who knows.”

Tom, if you’d just ask nicely for all the documents you want me to provide and be a little more polite and less condescending that’d be great and then maybe we could have a constructive dialog instead. I’m simply trying to understand your reasoning behind CAGW, not here to fight.

Here is the link to the NASA FOIA files part 4 containing all of the emails above and many more showing that these “experiments” were indeed the ones run by Reto, Gavin, and Andy to write their paper on the GHE [which was originally submitted to BAMS and rejected by all 3 reviewers, one of which Gavin suspects was Richard Lindzen as you will see from the emails].

Pekka, Eli, Tom, ATTP, Arthur, etc. in a comment above I asked Tom & ATTP to go on record as to what their best guess is for the total greenhouse and CO2 greenhouse net effects at the present non-equilibrium state, expressed as K and W/m2 at the surface and at the tropopause, and both before and after all feedbacks. Tom seems to reply above that’s not possible to provide, but I assume will consider this a misquote/misunderstanding as well.

May I ask all of you Pekka, Eli, Tom, ATTP, Arthur, etc. for your best estimates of these values so we are all on the “same” page, or why you cannot provide your best estimates of these values?

May I ask all of you Pekka, Eli, Tom, ATTP, Arthur, etc. for your best estimates of these values so we are all on the “same” page, or why you cannot provide your best estimates of these values?

Can you explain why? The reason I ask is because this is typically the precursor to “Ahah, you said X and therefore Y”, which is not really a game I feel like playing. Also, I largely agree with Arthur’s comment and that should really tell you all you need to know.

Also you still haven’t acknowledged that your rather simplistic calculation is essentially circular. If you took it to it’s logical conclusion, you could drive the CO2 response to zero (i.e., it contributes 20% of GHE, therefore using Otto et al., it is 0.25 degrees per doubling, therefore it only contributes 5% of GHE, therefore using Otto et al., it is 0.05 degrees per doubling, therefore it only contributes 1% of GHE, therefore using Otto et al. it is 0.01 degrees per doubling, etc.).

Here’s some emails from the FOIA file part 4 showing Gavin did those model E “experiments” above and wrote the GHE paper specifically because he couldn’t find anything in the literature that quantified the GHE due to water vapor vs. CO2, including the IPCC reports

As I already wrote the total GHE is given by the difference of surface temperature and the effective radiative temperature of the Earth as seen from the space. Without GHE that difference is zero, thus the actual value is the total GHE.

That value is not formed additively from several parts but is formed non-linearly from their combined influence. Therefore no way of telling without ambiguity, what’s the share of CO2, H2O or any other factor. An analysis like that performed by Gavin Schmidt and Andy Lacis explains that with the help of model calculations. Someone else would get a little different values from a similar calculation, even the same authors might now present somewhat different numbers, but all those calculations have only curiosity value.

What’s more important in practice is to estimate the influence of changes of the concentrations in the range that’s realistic in the foreseeable future. As we all know, even those numbers are known less accurately than is desirable.

(I don’t think that speculations on the properties of an Earth without CO2 helps in determining any of the climate sensitivity parameters.)

I entirely agree that dwelling on the unisolable 1.1C direct response to CO2 doubling is uninformative. By that logic we shouldn’t be dwelling on ECS either, yet people seem happy to blather on about it endlessly. The same applies to TCR estimates that fail to include slow feedbacks.

Ah, someone using the handle “Hockey Schtick” says he wants a constructive dialog with scientists. If true, he would have to start by dropping the handle and apologizing for having used it. Otherwise, not going to happen.

HS, you ask for a “best guess is for the total greenhouse and CO2 greenhouse net effects at the present non-equilibrium state, expressed as K and W/m2 at the surface and at the tropopause, and both before and after all feedbacks.” This request is, as far as I can understand it, meaningless in several respects, as the above discussion should have already made clear to you. The only meaningful portion of your request is what Pekka and Tom have already given above – the quantifiable greenhouse effect is the difference between average upwelling radiation from Earth’s surface and that at the top of the atmosphere, the roughly 155 W/m^2 that ATTP mentioned in the original post here. That corresponds to an equilibrium temperature change of about 33 K (or more), but that’s just a long-term response to restore balance; out of equilibrium there’s no particular temperature that can be attributed to the “total greenhouse” or any portion thereof. The greenhouse effect is a radiative energy flux issue, not a temperature change. The temperature response is merely the world trying to restore balance, however it does that, and there are many possible paths depending on ocean, biosphere, ice, etc. behavior that have nothing to do with the greenhouse gases themselves. So asking for the effect as a number of ‘K’ out of equilibrium is meaningless.

CO2’s direct contribution to the radiative energy flux change (from its spectral absorption properties) is about 19% (between 14 and 25%), according to this excellent post from Chris Colose – http://chriscolose.wordpress.com/2010/08/27/adding-up-the-greenhouse-effect-attributing-the-contributions/ – with water vapor about 50%, clouds about 25% etc. Including the fast feedbacks (water vapor and clouds) it’s close to 100% – and with slow feedbacks like ice, as Chris noted, models that remove all the CO2 lead to a “snowball earth” with much lower temperatures, so effectively much more than 100% of the present GHE is attributable to CO2 plus all the feedbacks.

But perhaps we would be more enlightened if you would tell us what YOUR “best guess” is for these things.

Arthur,
Chris’s post is great, thanks. Just reminds me that most of what I write has probably already been covered by others in a more thorough, clearer and better way. If my posts act to give people a chance to remind others (and myself) of what people have done before, I’ll count that as a success 🙂

I got to thinking about your ridiculous request for me to create my own GCM and measure every cells albedo affect and I recalled a Junior High School teacher showing us how to exactly compute PI using geometry.

Since I am an observational kind of guy, I put two flukes of a dinghy anchor up on deck, one of which was half black, half galvanized and the other fluke is all black. The all black fluke got hotter faster, but as of 5 minutes ago and the entire last hour, both flukes are the same 50.7˚C. I expect them to start cooling in a little while and the all black fluke to cool faster. I seem to recall doing a similar experiment in Grade School or Junior High.

I don’t think Bond Albedo means what you think it does, to quote Inigo Montoya, especially when it come to the S-B equation. Kirchhoff rules 🙂

To be honest I know this example doesn’t entirely refute the albedo premise, due to a little thing called equilibrium, but I bet you know where I am headed.

“Someone else would get a little different values from a similar calculation, even the same authors might now present somewhat different numbers, but all those calculations have only curiosity value.”

More than curiosity value, I think. Lindzen (or Singer) makes an often repeated claim that CO2 only contributes 2% to the greenhouse effect. If true, that would make plausible claims that most of the total greenhouse effect would remain intact even in the absence of CO2, ie, that the water vapour and cloud greenhouse effects were, or themselves, sufficient to maintain temperatures high enough to maintain approximately the current total column water vapour. So, having a reasonable estimate is relevant to knowing that that is not the case. Further, with a reasonable estimate, ball park estimates of important climate estimates (ECS, for example) can be made.

Of course, the questions that can be answered roughly by such estimates can be answered more accurately by other model experiments. Lacis et al 2010 is more scientifically informative than Schmidt et al 2010 (in other words).

That you would use so misrepresentative a label as CAGW shows otherwise. Nobody here believes is Catastrophic Anthropogenic Global Warming. Most, I suspect, accept the IPCC warnings of potentially catastrophic anthropogenic warming, but also potentially (though with lower probability) global warming so mildly harmful that mitigation would cost more than its effects. Note that mitigation is still the best economic option in that case because it has the highest probable return.

Likewise your repeated misrepresentation or simply ignoring of answers that you don’t like or can’t comprehend shows an unwillingness to understand our reasoning.

And, as pointed out above by Steve Bloom, somebody who chooses for a label a false accusation of scientific fraud cannot then claim to be interested in open discussion on the science without justifiable howls of laughter in response.

Genghis, you keep asserting that an expectation that you build your own climate model is ridiculous. The simple fact is that climate models are our means of determining the observational predictions of our physical theories when it comes to climate. Because climate systems are complex, we cannot do that with simple algebra but can with models.

Now, you want to assert an alternative physics to that used in current climate models (and backed by experimental observations). Fine, but if you are not simply wasting everybody’s time, you owe us the observable predictions – and those predictions need to be shown to follow from your alternate physics. Hence the need for the climate model. No model equals no predictions. Just assertions.

As it happens, using the standard physics, models have been developed at every level (including some by SOD for blog posts) which successfully predict earth like climates and weather patterns, and with considerable success predict the actual changes in the Earth’s climate. Against that predictive success you offer us nothing.

Put another way, if you want to take us back to pre-1971 science, you need to do the scientific legwork. Otherwise I, at least and from now on, will simply ignore you.

“Here’s some emails from the FOIA file part 4 showing Gavin did those model E “experiments” above and wrote the GHE paper specifically because he couldn’t find anything in the literature that quantified the GHE due to water vapor vs. CO2, including the IPCC reports”

First, Ramathan and Coakley (1978)* did quantify the effects of CO2, H2O, O3 and clouds, as did Manabe and Strickland and Manabe and Wetherald. Those quantifications may have been dated, and crude in technique compared to Schmidt et al (2010), but that does not mean they did not quantify the effects. It would be nice if you would cease your perpetual misrepresentations.

Second, the contrast between Schmidt and Lindzen’s responses to the limited quantification is instructive. Lindzen (in a 1991 book review) seems to have simply made up a figure that suited his narrative. Schmidt, in contrast, used a model to determine a rough answer (because based only on a single day) for a blog post; and then conducted extensive model experiments to find a better estimate which he published in the scientific literature. The contrast in behaviour is noteworthy and instructive.

Third, in the paper itself, Schmidt et al also mention Kiehl and Trenberth (1997), who also make an estimate of relative contribution based on a representative atmospheric profile in a LBL radiation model. I am not sure what advantage you gain in scouring emails to show that scientists do not know as much before they commence a study as they do afterwards.

* Note: google scholar shows several citations to an article or presentation by Ramathan and Coakley which by title more directly addresses the issue. As the figures quoted by Schmidt for Ramathan and Coakley differ from those in the paper to which I linked, they may well have come from that cited article of which I cannot find a copy on the internet.

Robert Scribbler has gathered a little more on the southeast Brazil drought. It seems that if it doesn’t rain in the next couple months, a city with a population of 20 million will be struck by a catastrophic, um, … failure of governance. Yes, that’s it. Nothing to do with climate. Had the past political leadership been sufficiently libertarian, surely they’d have been motivated to plan for long-range environmental catastrophes of this sort.

Ohh, one last thing ATTP now that I am not being let through moderation, your explanation between GR and Special relativity was correct, but if you actually look at the data you will see that the clocks on the satellites run faster. Just a little something I picked up designing guidance systems.

Reality is messy. You might have the right theory and still get the wrong answer. Good luck.

I think it’s time to take up cycling for my health (or peddling, anyway ;)), so in response to Steve Bloom:

In Nov 2010, the water supply for the City of Brisbane was at 10% of capacity due to a prolonged drought. Severe water restrictions and the construction of a water desalinization plant had eeked out existing water stocks by a year of normal consumption, which out which measures Brisbane would already have gone dry. In Dec 2010, we had extensive rain around Christmas, partly refilling the dam. That did not stop the then leader of the conservative (but not libertarian) opposition from berating the government for not lifting the rated capacity of the dam, thereby using some flood mitigation capacity as extra water storage.

Instantly the received wisdom became the foolishness of building the desalinization plant. The dam is now limited to 80% of its rated storage capacity to allow for extra flood mitigation (a policy adopted by the party that had berated the then government for not having the opposite policy just months before, and two weeks before the flood). This in spite of the fact that the massive turn around in water supply was the result of unprecedented flooding across Queensland, and the Brisbane flood itself the consequence of two one in two hundred year rainfall events in the same small catchment within a week of each other.

My first point in this is that Sao Paulo is not yet doomed. Miracles like the Brisbane 2011 flood do happen, and Sao Paulo could yet be swimming in water within two months.

However, it is a foolish polity that banks on it. And an even more foolish political outlook that assumes that dams will never run dry because mitigation (or adaption) is too expensive.

I must admit that I thought that relative the clock on the surface, the clock in orbit would run very slightly faster as it was higher in the gravity well. I hadn’t even considered orbital velocity/special relativity but that’s what we have physicists for 😉

Right, Tom. Actually I do recall reading about Brisbane at the time. I’m not sure why, but while similar arguments could have happened here in California re storage vs. flood protection, they don’t seem to have. Generally people seen happy to leave those sorts of calls to the water bureaucrats. There has been a kerfuffle over the first big desal plant, though, and Jerry Brown’s scheme to increase north-south water export capacity is encountering much flak. It’s interesting that he seems unwilling to make the most straightforward argument for bypassing the Delta, which is that with continued SLR it’s only a matter of time before salt water starts having a major impact on the existing canal intakes. Possibly it’s because that would be admitting that the (iconic) Delta is pretty much toast.

Re Sao Paulo, I hope you’re right. Looking at the situation globally, I expect we’ll see an increasing frequency of close calls until eventually one actually goes over the edge. Arguably that already happened in Syria, albeit sans a megalopolis.

I’m very curious about the history of and what the models may have to say about this particular drought pattern, but haven’t been able to find much information. It’s clearly more extreme relative to the (less than a century) record, but is it really new? It’s interesting that while the Amazon is the moisture source for the usual summer rains, the Amazon region itself doesn’t seem to be currently in drought, nor does Sao Paulo seem to have suffered in 2005 or 2010.

If anyone reading has any insights or especially links on this topic, please do weigh in. Richard?

Tom,
Thanks. I stand corrected then. I had never actually done the calculation and just assumed SR would be the dominant effect. Seems not. So, SR + GR means the satellite clocks run slightly faster than those on the ground.

Tom Curtis, these forums do seem to involve a lot of peddling for some.

Steve Bloom, Andrew Dodds, This has played out before. During Irish Potato Famine, free market ideals were hauled out in the face of certain starvation for Irish. Britain had the food, but exported it amid considerable controversy. Libertarianism won that time! *phew*

Tom Curtis, thanks for that bit on relativity. I deal with clock drift a lot in communications, although I’m pretty sure my error margins are far larger than anything relativistic. Its typically the first and hardest problem in any system. If my clock is 500PPM fast, and yours is 50PPM slow, how long till the data can’t decode data bits that are 12us wide? Further more obtaining a strong initial time value is also critical. This is where you see sync patterns.

I worked on one frequency hopping system in which we had to track not only where something was, but when it was. We could track everyone else’s relative clock drifts.

It’s remarkable how when asked to provide people’s best estimates of the present, non-equilibrium GHE in terms of total and the CO2 component everyone here essentially claims it can’t be done and allegedly “makes no sense,” and then goes on to link to Gavin, RealClimate, Chris Colose, etc. where in fact those best estimates are provided. Here’s what those links say:

“The overlaps complicate things, but it’s clear that water vapour is the single most important absorber (between 36% and 66% of the greenhouse effect), and together with clouds makes up between 66% and 85%. CO2 alone makes up between 9 and 26%, while the O3 and the other minor GHG absorbers consist of up to 7 and 8% of the effect, respectively. The remainders and uncertainties are associated with the overlaps which could be attributed in various ways that I’m not going to bother with here. Making some allowance (+/-5%) for the crudeness of my calculation, the maximum supportable number for the importance of water vapour alone is about 60-70% and for water plus clouds 80-90% of the present day greenhouse effect. (Of course, using the same approach, the maximum supportable number for CO2 is 20-30%, and since that adds up to more than 100%, there is a slight problem with such estimates!).”

“In terms of the percent contributions after allowing for overlap effects when discussing the individual agents in the atmosphere, here are the numbers that should be cited:

Water Vapor: 50%
Clouds:25%
CO2: 19%
Other (ozone, methane, etc): 7%”

ATTP’s post above “The greenhouse effect refers to the fact that our surface temperature is 33 degrees higher than it would be if our atmosphere was completely transparent to our emitted radiation (assuming a fixed albedo). A 33 degree increase in surface temperature is associated with a 155 Wm-2 increase in surface flux, or a 122 Wm-2 change in radiative forcing (33 x 3.7Wm-2). The actual number isn’t that important for this discussion, though. Prior to the increase in anthropogenic CO2, the atmospheric CO2 concentration was about 280ppm. This would contribute a radiative forcing of about 30Wm-2, so about 20% of the the overall greenhouse effect.”

Therefore, the calculations I have shown several times above are right in this same range and don’t change TCR significantly whether one assumes CO2 is 19 to 30% of the “present day” 33K GHE after feedbacks, and thus demonstrate TCR is low, even if one assumes all warming since 1850 to be anthropogenic.

From this TCR calculation, assume whatever unreasonably high estimate for ECS, say 500% of TCR, one still arrives at an unimpressive, low ECS.

HS,
But your calculation is nonsense. That’s the problem. Firstly, we are not currently in equilibrium. Secondly, we don’t know that the Otto et al. (or Lewis et al.) calculation is actually correct. We don’t know that the ECS will always be 130-150% of the TCR. Let’s also clarify what the papers discussed here are actually saying. They’re saying that a single factor removal of CO2 shows that it contributes less than 20%. However, a single factor addition indicates that it contributes 25% (in other words, if it were the only change it would produce 25% of the warming, but because there are overlapping spectral bands, its removal only has a 20% – or less – effect).

To be honest, I see no great value in continuing this discussion. As I’ve already pointed out, earlier discussions with you have indicated that you dispute (deny) the mainstream explanation for the greenhouse effect. You here are trying to suggest that a doubling of CO2 would somehow produce a very low TCR/ECS, ignoring that the feedbacks amplify the warming and appearing to misunderstand the difference between single factor removal and single factor addition. The greenhouse effect is consistent with an ECS between 3 and 4 degrees. That’s probably all that we can actually say. Circular arguments using Otto et al. and low TCR to ECS ratios are neither illuminating nor – probably – correct.

You appear to be so far outside the mainstream that either you should publish your seminal paper and collect your Nobel prize, or you should stop wasting everyone else’s time.

[Mod : Sorry, I no longer have a clue what you’re getting at. Somehow a greenhouse effect that is consistent with an ECS of between 3 and 4 degrees is also consistent with a much lower ECS. That doesn’t make any sense to me. Maybe it makes some kind of sense to you, but I fail to see how it can.]

ATTP, are you really not going to publish my comment? What’s the harm in doing so, as everyone here loves to rip to shreds anyhow? Why deprive them of that opportunity?

“Somehow a greenhouse effect that is consistent with an ECS of between 3 and 4 degrees is also consistent with a much lower ECS. That doesn’t make any sense to me. ”

I am showing that given the “mainstream” percentage contributions as quoted above of the present-day non-equilibrium 33K GHE, you would have to assume that ECS was ~1800%+ of the calculated TCR over the past 160 years to get to 3.5-4C ECS, which doesn’t make sense.

I am showing that given the “mainstream” percentage contributions as quoted above of the present-day non-equilibrium 33K GHE, you would have to assume that ECS was ~1800%+ of the calculated TCR over the past 160 years to get to 3.5-4C ECS, which doesn’t make sense.

No, that is not what you’re doing. That’s what you claim you’re doing, but it isn’t what you’re actually doing. I have no great interest in continuing to play this game. I’ve let you (a self-avowed denier) comment here more than I normally would simply because you have been more polite than is normally the case. You know (and I know) that this isn’t going to be constructive, so let’s not pretend that there is any chance that it will be.

1) What you asked, and what I pointed out is meaningless, is the question:

“I don’t want to misquote anyone, so would you and Tom Curtis please clarify for the record what your best estimate is of the total GHE before and after all feedbacks, and what your best estimate is of the CO2-only GHE contribution before and after all feedbacks. Please state both in terms of W/m2 forcing at the surface and degrees K at the surface.”

(Emphasis added)

What I pointed out is that the total GHE effect is the difference between upward radiation at the surface and at the TOA. We can meaningfully quote the TGE, and we can meaningfully quote forcing at the surface. We cannot quote total GHE at the surface any more than you can quote the volume of a cube “at the surface”.

I further pointed out that the single factor values quoted by Schmidt et al are the values excluding feedbacks.

Until you acknowledge these two important points it is pointless quoting specific numbers because you will merely misrepresent them.

Just so we are clear. The approximately 75% of the Total Greenhouse Effect due to water vapour and clouds are feedbacks. All of it! If we wanted a gross simplification we might attribute 80% of that feedback to CO2, so that the total effect of CO2 on the Total Greenhouse Effect is of CO2 including the effect of feedbacks on the initial effect of the CO2 would be 80% (124 W/m^2), but there are non-linearities involved so that is a gross simplification. It is also, because of overlaps, very approximate.

Actual CO2 removal experiments such as those by Lacis et al show that more than that amount of water vapour plus cloud contribution to the Total GHE is removed under those circumstances, showing that estimate to be a gross simplification as noted. In particular, there is in addition to the direct feedback effects on the Total Greenhouse Effect, and indirect effect through strong positive feedbacks related to albedo (with the positive feedbacks in the cryosphere overwhelming the negative cloud feedbacks) which contributes a further indirect feedback in the Total Greenhouse Effect.

“I am showing that given the “mainstream” percentage contributions as quoted above of the present-day non-equilibrium 33K GHE, you would have to assume that ECS was ~1800%+ of the calculated TCR over the past 160 years to get to 3.5-4C ECS, which doesn’t make sense.”

Bullshit!

You are showing that if you pull numbers out of context without understanding what they represent, you can massage them unethically to produce the message you want to sell. What is more, you are doing so in the face of the direct warning in the paper from which you derive your figures that what you are doing is invalid. Specifically, Schmidt et al state:

“It is in part due to these non-linearities combined with associated feedbacks that the attribution calculations are not directly useful for determining climate sensitivity. For
instance, one can’t simply take the attribution to CO2 of the total greenhouse effect (20%
of 33◦C) and project that onto a 2×CO2 scenario. That would exaggerate the no-feedback
impact of the extra CO2 while ignoring the role of feedbacks that might change the water
vapour and clouds.

Taking “…the attribution to CO2 of the total greenhouse effect (20% of 33◦C) and project[ing] that onto a 2×CO2 scenario” is in essence what you are doing. The TCR includes feedback. The only subtlety you add is that you multiply the projection by the purported ratio between ECS and TCR. The TCR, however, already includes feedbacks. Therefore the CO2 only addition to the Total GHE is not the TCR response but much less than that. If you are going to multiply out by anything it should be the ratio of the ECS to the direct temperature response to the initial forcing (approximately 2.25 for GISS model E) but to do that you must already have an estimate of ECS. Even that, however, ignores the non-linearities so that it is essentially meaningless except as a ball park estimate. It is a zeroth order approximation. It gets the order of magnitude right, but cannot be relied on beyond that (a point I made before you intruded onto the conversation). So at best, doing so means that you are using a more certain estimate of ECS to determine an less certain estimate of ECS, and concluding from that the the more certain estimate is in error.

It’s all schtick, so why argue with him? He’s no different than the Cappy character who was doing a Professor Irwin Corey impersonation. Cappy called his blog Redneck Physics, and this guy calls his Hockey Schtick. Can it be any more obvious that they are just trying to pull our chain?

at the NOAA site for reports on global analysis, state of the climate, last November was the hottest November in recorded history (since the late 1800s, right?), last April tied for the hottest April in recorded history, last May was the hottest May in recorded history, last June was the hottest June in recorded history, and last August was the hottest August in recorded history. We’ll see whether the NOAA agrees with NASA that this last month of September was the hottest September in recorded history. That is, according to the NOAA, assuming they agree with NASA on September, then we had the hottest global temperatures in recorded history equaled or set in 5 of the past 6 months, and 6 of the last 11 months. And we have all this without El Nino.

It looks like the planet is denying the deniers – especially the global cooling peddlers. The laws of physics don’t seem to want to break themselves for the deniers.

But on a more serious note, I do have some questions:

If all the most recent global data, including even this very most recent data, were included, then to what degree would that throw a monkey wrench into the calculations or conclusions of the recent papers by such as Curry that go against mainstream climate science?

I understand that she did not include all relevant data even in the time periods covered in her recent papers. Perhaps including all the data, including all the most recent data, would falsify (even a sort of soft core falsification, in the form of an increase in the implausibility of her results, would do) her recent results, even if we were to grant (at least some of?) her assumptions?

I mean, she claims to be “data-driven”, right? But she does not include all the data.

Also, would including all the most recent data – especially all this recent record equaling and breaking data – be enough to change statistically insignificant surface warming to statistically significant surface warming for some time periods starting roughly since the mid or late 1990s to early 2000s up to the present, and if so, what would they be?